Challenges Toward Wireless Communications for High-Speed Railway

Abstract

High-speed railway (HSR) brings convenience to peoples' lives and is generally considered as one of the most sustainable developments for ground transportation. One of the important parts of HSR construction is the signaling system, which is also called the "operation control system," where wireless communications play a key role in the transmission of train control data. We discuss in detail the main differences in scientific research for wireless communications between the HSR operation scenarios and the conventional public land mobile scenarios. The latest research progress in wireless channel modeling in viaducts, cuttings, and tunnels scenarios are discussed. The characteristics of nonstationary channel and the line-of-sight (LOS) sparse and LOS multiple-input-multiple-output channels, which are the typical channels in HSR scenarios, are analyzed. Some novel concepts such as composite transportation and key challenging techniques such as train-to-train communication, vacuum maglev train techniques, the security for HSR, and the fifth-generation wireless communications related techniques for future HSR development for safer, more comfortable, and more secure HSR operation are also discussed.

FSO G2T communications in tropical climate: An overview

“…Additionally, special track alignment scenarios and combinations may cause signal loss due to reflection, scattering, obstruction or scattering [28].Some of these scenarios include rail sideway furniture such as crossings, cuttings, tunnels, viaducts, tunnel groups, railway stations, crossing bridges and different super elevations.…”

“…In FSO links, mitigation techniques include Aperture averaging, diversity, hybrid RF/FSO. Finally, RF key technologies include, LTE-R, 5th generation technologies (5G), internet of things (IOT) and self-organizing networks (SON) [28].…”

The Evolution of Key Technologies of Mobile Communication Systems for High-speed Railway

“…The introduction of an in-vehicle access system (Femto system), WiFi and other in-car access system in the train provides a good solution for these problems. Based on the above functional requirements, there are still a series of technical standards and key technologies to be solved, including the next generation of mobile communication networks and wireless local area network access, vehicle wireless connection, large-capacity concurrent signaling storm, vehicle connection equipment and cabins Interference between devices into the coordination and so on [7] .…”

Indoor massive multiple-input multiple-output channel characterization and performance evaluation

“…To achieve the best spectrum utilization, massive MIMO systems working at the frequency bands below 6 GHz are expected to support large coverage and provide a moderate transmission rate for user experience, whereas the systems working at the frequency bands above 6 GHz are expected to serve in short-range communications and carry out wide-bandwidth and high-speed transmissions. Since the system performance can be seriously affected by the radio channels, in-depth investigations into channel behaviors for typical scenarios (e.g., indoor halls, theaters, railway stations (Guan et al, 2014a), and railways (Gao et al, 2010;Guan et al, 2013a;2014b;Ai et al, 2014;) at different frequency bands are needed. Wu et al (2015) proposed a non-stationary wideband channel model for massive MIMO, and investigated the statistical properties of the channel model by numerical analysis; however, no measurement-based verification was done.…”